The birth control shot, or Depo-Provera, also contains progestin, which is the hormone that prevents ovulation.

Progestin, which all pills and shots use, prevents the ovaries from releasing an egg. This makes pregnancy very unlikely. The hormone can also make the lining of the uterus less favorable for an egg to implant.

The estrogen component in the combination pills actually thickens the uterine lining, which provides stability and controlled bleeding patterns. This is why people taking the combination pill usually have a regular monthly period.

Effectiveness

About 6 out of every 100 women who have the shot will become pregnant within the first year.

About 9 out of every 100 women who take the pill will become pregnant within the first year.

If someone does not get the shot as regularly as every 3 months, they have a greater likelihood of becoming pregnant.

Likewise, if a person misses a pill or takes it later than the ideal time, this could make the pill less effective.

Certain medicines can interfere with both the birth control shot and pills, which could reduce their effectiveness. A person should ask their doctor about drug interactions when taking a new medicine, including antibiotics.

If someone wants to become pregnant after stopping birth control injections, it takes 10 months, on average.

Side effects

Both birth control shots and pills may cause headaches.

As with most medications, birth control pills and the shot have side effects. People may wish to discuss these with their doctor when considering the best option for them.

The side effects are similar for the shot and pills because they contain similar hormones.

Doctors may advise that a person receiving birth control shots take calcium supplements to reduce the risk of bone loss. When they stop receiving birth control injections, they will usually gain lost bone back.

Doctors associate the mini-pill with fewer side effects than combination contraceptives.

In rare cases, taking the combination pill can cause blood clots and a higher risk of heart attack and stroke. People are more likely to experience these complications if they are older than 35, if they smoke, or if they have a history of migraine.

Bleeding patterns

With the shot, people may experience more sporadic bleeding patterns, but as time goes on, they tend to have much lighter, less frequent episodes of bleeding.

Some people even have total absence of periods after a while. The one drawback is that they will not necessarily know when they are going to bleed.

With pills, people may have irregular bleeding initially, but generally, this will become a regular predictable bleed each month.

People can also take pills on an extended cycle to avoid having periods every month. For the most part, they will know when to expect a period. However, if they miss pills, they may bleed unexpectedly.

Cost

The cost of birth control varies depending on manufacturers and types. Health insurance companies and family planning clinics often cover or discount the costs of birth control pills and shots.

According to the National Women’s Health Network, one birth control shot costs $60. Birth control pills typically cost up to $50 per month, but generic forms of pills can cost as low as $10 per month.

Which one is right for me?

The birth control pill can help regulate a person’s menstrual cycle.

When a person uses them as a healthcare professional directs, birth control pills and the shot can both effectively prevent pregnancy.

Some of the major considerations include:

Convenience. If someone is worried that they will not be able to take their pills at the same time every day, they may prefer the shot. If they do not want to go back to the doctor’s office every 3 months, birth control pills may be more convenient.

Bleeding patterns. Both the shot and pills can cause changes in menstruation. The shot can make periods lighter, less frequent, and unpredictable for some people. Combination pills can help regulate a person’s menstrual cycle and allow them to predict when their period arrives.

Effectiveness. Both contraceptive methods have similar effectiveness when a person uses them appropriately, though the shot may be slightly more effective than the pill.

Side effects. Both methods have side effects. Some people may have different side effects than others, as each person’s body reacts differently to hormones.

Cost. The cost of the pills and the shot can be similar depending on a range of factors, such as brands, a person’s insurance, and whether they are able to get the birth control from a family planning clinic.

Alternative birth control options

Aside from the shot and pills, people can use other prescription or nonprescription methods of preventing pregnancy.

Nonprescription birth control options include:

female condoms

male condoms

spermicides

sponges

Prescription methods include:

diaphragms

implantable rods

intrauterine devices

patches

vaginal rings

People can use a prescription or nonprescription method together with male or female condoms for protection against sexually transmitted infections (STIs). Sponges and spermicide may not prevent STIs.

Summary

Birth control pills and the birth control shot are both effective ways to prevent pregnancy. Both use similar hormones, so they also have similar side effects and risks.

Some people prefer the convenience of only having to get a birth control injection every 3 months, while others may not like having to make extra appointments with their doctor.

Ultimately, a person should consider many factors when determining what option may work best for them.